BACKGROUND: Recent neuroimaging studies in humans support the clinical observations that the motor cortex is affected early in the course of Alzheimer's disease (AD). METHODS: We used transcranial ... [more ▼]

BACKGROUND: Recent neuroimaging studies in humans support the clinical observations that the motor cortex is affected early in the course of Alzheimer's disease (AD). METHODS: We used transcranial magnetic stimulation to measure the active cortical motor threshold (ACMT) in AD patients in the very early stage of the disease, and we explored whether and in which way the pharmacologic manipulation of the cholinergic system could have a direct effect on the excitability of the motor cortex. RESULTS: An increase of the ACMT was observed in AD patients in the early stage in comparison to controls. After 2 months of treatment with donepezil, the threshold did not differ significantly from normal subjects. CONCLUSIONS: The results suggest an early functional impairment of cholinergic neurotransmission in AD, which is associated to early changes in the excitability of the motor system. [less ▲]

Background: Transcranial magnetic stimulation (TMS) has been frequently used to explore changes in the human motor cortex in different conditions, while the extent of motor cortex reorganization in ... [more ▼]

Background: Transcranial magnetic stimulation (TMS) has been frequently used to explore changes in the human motor cortex in different conditions, while the extent of motor cortex reorganization in patients in vegetative state (VS) (now known as unresponsive wakefulness syndrome, UWS) and minimally conscious (MCS) states due to severe brain damage remains largely unknown. Objective/hypothesis: It was hypothesized that cortical motor excitability would be decreased and would correlate to the level of consciousness in patients with disorders of consciousness. Methods: Corticospinal excitability was assessed in 47 patients (24 VS/UWS and 23 MCS) and 14 healthy controls. The test parameters included maximal peak-to-peak M-wave (Mmax), F-wave persistence, peripheral and central motor conduction times, sensory (SEP) and motor evoked (MEP) potential latencies and amplitudes, resting motor threshold (RMT), stimulus/response curves, and short latency afferent inhibition (SAI). TMS measurements were correlated to the level of consciousness (assessed using the Coma Recovery Scale-Revised). Results: On average, the patient group had lower Mmax, lower MEP and SEP amplitudes, higher RMTs, narrower stimulus/response curves, and reduced SAI compared to the healthy controls (P < 0.05). The SAI alterations were correlated to the level of consciousness (P < 0.05). Conclusions: The findings demonstrated the impairment of the cortical inhibitory circuits in patients with disorders of consciousness. Moreover, the significant relationship was found between cortical inhibition and clinical consciousness dysfunction. [less ▲]

OBJECTIVE: A 'case scenario' study on clinical decisions in progressing Parkinson's disease (PD) was developed to complement scientific evidence with the collective judgment of a panel of experts. METHODS ... [more ▼]

OBJECTIVE: A 'case scenario' study on clinical decisions in progressing Parkinson's disease (PD) was developed to complement scientific evidence with the collective judgment of a panel of experts. METHODS: The opinions of 9 experts in movement disorders on the appropriateness of 9 common pharmacological treatments for 33 hypothetical patient profiles were compared to those of 14 general neurologists. Before rating the case scenarios, all participants received a document integrating European and US guidelines for the treatment of patients with advanced PD. Case scenarios showing disagreement or with inconsistencies in appropriateness ratings were discussed at a feedback meeting. A tool for interactive discussion on the clinical case scenarios included was developed based on the outcome of the study. RESULTS: Current guidelines are often insufficient to adequately guide the management of patients with progressing PD. The case scenario study did not reveal major differences in opinions between experts in movement disorders and general neurologists about the appropriateness of certain drug choices for specific case scenarios. However in about 1 out of 5 treatment decisions where experts stated appropriateness or inappropriateness, the general neurologists panel had no or dispersed opinions. CONCLUSIONS: This study reveals more uncertainty about treatment of advanced PD in general neurologists compared with experts in movement disorders and underlines the need for additional support for guiding treatment decisions in clinical practice. [less ▲]

The cause of Parkinson's disease remains unknown and no cure or prevention exists so far. Levodopa remains by far the most potent symptomatic therapy, but induces side-effects such as motor fluctuations ... [more ▼]

The cause of Parkinson's disease remains unknown and no cure or prevention exists so far. Levodopa remains by far the most potent symptomatic therapy, but induces side-effects such as motor fluctuations and abnormal movements, which can somewhat be counterbalanced by optimizing levodopa plasma levels or acting at receptors level with long half-life dopamine agonists. In severe cases, functional surgery with deep brain stimulation can be offered. Some non-dopaminergic symptoms like dementia, freezing, postural instability or dysautonomia do not respond to dopaminergic drugs and need special care. [less ▲]

Transcranial magnetic stimulation (TMS) is a noninvasive means of investigating the function, plasticity, and excitability of the human brain. TMS induces a brief intracranial electrical current, which ... [more ▼]

Transcranial magnetic stimulation (TMS) is a noninvasive means of investigating the function, plasticity, and excitability of the human brain. TMS induces a brief intracranial electrical current, which produces action potentials in excitable cells. Stimulation applied over the motor cortex can be used to measure overall excitability of the corticospinal system, somatotopic representation of muscles, and subsequent plastic changes following injury. The facilitation and inhibition characteristics of the cerebral cortex can also be compared using the modulatory effect of a conditioning stimulus preceding a test stimulus. So called paired-pulse protocols have been used in humans and animals to assess GABA (gamma-amino-butyric acid)-ergic function and may have a future role directing therapeutic interventions. Indeed, repetitive magnetic stimulation, where intracranial currents are induced by repetitive stimulation higher than 1 Hz, has been shown to modulate brain responses to sensory and cognitive stimulation. Here, we summarize information gathered using TMS with patients in coma, vegetative state, and minimally conscious state. Although in the early stages of investigation, there is preliminary evidence that TMS represents a promising tool by which to elucidate the pathophysiological sequelae of impaired consciousness and potentially direct future therapeutic interventions. We will discuss the methodology of work conducted to date, as well as debate the general limitations and pitfalls of TMS studies in patients with altered states of consciousness. [less ▲]

Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we ... [more ▼]

Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we systematically stimulated the entire occipital cortex using single pulse transcranial magnetic stimulation (TMS) in early blind subjects and in blindfolded seeing controls. Whereas blindfolded seeing controls reported only phosphenes following occipital cortex stimulation, some of the blind subjects reported tactile sensations in the fingers that were somatotopically organized onto the visual cortex. The number of cortical sites inducing tactile sensations appeared to be related to the number of hours of Braille reading per day, Braille reading speed and dexterity. These data, taken in conjunction with previous anatomical, behavioural and functional imaging results, suggest the presence of a polysynaptic cortical pathway between the somatosensory cortex and the visual cortex in early blind subjects. These results also add new evidence that the activity of the occipital lobe in the blind takes its qualitative expression from the character of its new input source, therefore supporting the cortical deference hypothesis. [less ▲]

To study the functional involvement of the visual cortex in Braille reading, we applied repetitive transcranial magnetic stimulation (rTMS) over midoccipital (MOC) and primary somatosensory (SI) cortex in blind subjects. After rTMS of MOC, but not SI, subjects made significantly more errors and showed an abolishment of the improvement in reading speed following repetitive presentation of the same word list, suggesting a role of the visual cortex in repetition priming in the blind. [less ▲]

We describe the case of a 29 year old patient who presented severe myalgias and asthenia for 3 months. First biological assessment revealed muscular lysis and raised transaminases. The following ... [more ▼]

We describe the case of a 29 year old patient who presented severe myalgias and asthenia for 3 months. First biological assessment revealed muscular lysis and raised transaminases. The following complementary screening showed major hypothyroidism with the presence of anti-microsomes antibodies, a carpian canal syndrome and a left ventricular systolic dysfunction. A diagnosis of hypothyroidic rhabdomyolysis consecutive to a Hashimoto disease was then mash. Patient was treated by hormonal thyroid substitution with a progressive improvement of muscular symptoms to complete recovery, and a concomitant normalization of cardiac and thyroid functions. [less ▲]